Working Papers

Economic evaluation of climate policy traditionally treats uncertainty by appealing to expected utility theory. Yet our knowledge of the impacts of climate change may not be of sufficient quality to justify probabilistic beliefs. In such circumstances it has been argued that the axioms of expected utility theory may not be the the correct standard of rationality. By contrast several recently-proposed axiomatic frameworks account for ambiguous beliefs. We follow this approach and apply static and dynamic versions of a smooth ambiguity model to climate policy, obtaining general results on the comparative statics of optimal abatement and ambiguity aversion and illustrating this sufficient condition in some simple examples. Greater ambiguity aversion may lead to more or less abatement dependin...